In racing cars, newly constructed or converted from stock cars, electrical switches for starter, ignition, fuel, and water pumps, gauge and head lamps, are installed randomly wherever there is room using whatever types of switches and connectors are available. Often this results in use of improperly rated switches and improper wire sizes. Further, there is no standard provision for safety interlocks, such as for example precluding operation of fuel pumps when the ignition switch is off. In the usual installation yards of wire are led all over the car to provide power to each switch and connect each switch to the accessory. In the process of coursing the wires about the car, safety fusing is often completely overlooked. At best the fuses are installed randomly and in locations which make access difficult. Such installation using wires to interconnect the switches detracts seriously from the life of the switches: race cars produce strong and continuous vibration and the frequency of vibration of the free wire is quite mismatched with that of the switch lug to which it is attached. This mismatch accelerates loosening of the lug in the switch and can result in premature switch failure.